Re: [PATCH v17 1/7] firmware: arm_rmm: Add SMC definitions for calling the RMM

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 08/09/2026 07:19, Gavin Shan wrote:
> Hi Suzuki,
> 
> On 9/7/26 7:59 PM, Suzuki K Poulose wrote:
>> From: Steven Price <steven.price@arm.com>
>>
>> The RMM (Realm Management Monitor) provides functionality that can be
>> accessed by SMC calls from the host.
>>
>> The SMC definitions are based on DEN0137[1] version 2.0-bet3
>>
>> [1] https://developer.arm.com/documentation/den0137/2-0bet3/
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

...

>> ---
>>   include/linux/arm-smccc-rmi.h | 494 ++++++++++++++++++++++++++++++++++
>>   1 file changed, 494 insertions(+)
>>   create mode 100644 include/linux/arm-smccc-rmi.h
>>
> 
> Some nitpicks below, please pick up the commits that look reasonable :)
> 


>> +
>> +#define RMI_RETURN_STATUS_MASK        (0xFFUL)
>> +#define RMI_RETURN_INDEX_MASK        (0xFFUL << 8)
>> +#define RMI_RETURN_MEMREQ_MASK        (0x3UL << 8)
>> +#define RMI_RETURN_CAN_CANCEL_MASK    (0x1UL << 10)
>> +
>> +#define RMI_RETURN_STATUS(ret)        
>> FIELD_GET(RMI_RETURN_STATUS_MASK, ret)
>> +#define RMI_RETURN_INDEX(ret)        FIELD_GET(RMI_RETURN_INDEX_MASK, 
>> ret)
>> +#define RMI_RETURN_MEMREQ(ret)        
>> FIELD_GET(RMI_RETURN_MEMREQ_MASK, ret)
>> +#define RMI_RETURN_CAN_CANCEL(ret)    
>> FIELD_GET(RMI_RETURN_CAN_CANCEL_MASK, ret)
>> +
> 
> If I'm correct enough, RMI_RETURN_{STATUS, INDEX, MEMREQ, CAN_CANEL} 
> _MASK are used
> for once in this header file. So we needn't explicitly expose them and 
> combine their
> definitions with users to fetch the corresponding fields, as below.
> 
> #define RMI_RETURN_STATUS(ret)        FIELD_GET(GENMASK(7, 0), ret)
> #define RMI_RETURN_INDEX(ret)        FIELD_GET(GENMASK(15, 8), ret)
> #define RMI_RETURN_MEMREQ(ret)        FIELD_GET(GENMASK(10, 8), ret)
> #define RMI_RETURN_CAN_CANCEL(ret)    FIELD_GEt(GENMASK(10, 10), ret)

I belive the header files were generated from a tool (by Steven) and
these would make it easier to compare with the generated header file for
any deviation from the spec. So, I am a bit reluctant make these
changes.

That said, I am happy to convert the mask definitions to GENMASK() for
consistency and readability. i.e., something like:

diff --git a/include/linux/arm-smccc-rmi.h b/include/linux/arm-smccc-rmi.h
index 3eb88caf40964..078197284415e 100644
--- a/include/linux/arm-smccc-rmi.h
+++ b/include/linux/arm-smccc-rmi.h
@@ -139,10 +139,10 @@
  #define RMI_ABI_VERSION_GET_MINOR(version) ((version) & 0xFFFF)
  #define RMI_ABI_VERSION(major, minor)      (((major) << 16) | (minor))

-#define RMI_RETURN_STATUS_MASK         (0xFFUL)
-#define RMI_RETURN_INDEX_MASK          (0xFFUL << 8)
-#define RMI_RETURN_MEMREQ_MASK         (0x3UL << 8)
-#define RMI_RETURN_CAN_CANCEL_MASK     (0x1UL << 10)
+#define RMI_RETURN_STATUS_MASK         GENMASK(7, 0)
+#define RMI_RETURN_INDEX_MASK          GENMASK(15, 8)
+#define RMI_RETURN_MEMREQ_MASK         GENMASK(10, 8)
+#define RMI_RETURN_CAN_CANCEL_MASK     BIT(10)


> 
>> +#define RMI_SUCCESS            0
>> +#define RMI_ERROR_INPUT            1
>> +#define RMI_ERROR_REALM            2
>> +#define RMI_ERROR_REC            3
>> +#define RMI_ERROR_RTT            4
>> +#define RMI_ERROR_NOT_SUPPORTED        5
>> +#define RMI_ERROR_DEVICE        6
>> +#define RMI_ERROR_RTT_AUX        7
>> +#define RMI_ERROR_PSMMU_ST        8
>> +#define RMI_ERROR_DPT            9
>> +#define RMI_BUSY            10
>> +#define RMI_ERROR_GLOBAL        11
>> +#define RMI_ERROR_TRACKING        12
>> +#define RMI_INCOMPLETE            13
>> +#define RMI_BLOCKED            14
>> +#define RMI_ERROR_GPT            15
>> +#define RMI_ERROR_GRANULE        16
>> +
>> +#define RMI_CONTINUE_KEEP_GOING        0
>> +#define RMI_CONTINUE_STOP        1
>> +
>> +#define RMI_OP_MEM_REQ_NONE        0
>> +#define RMI_OP_MEM_REQ_DONATE        1
>> +#define RMI_OP_MEM_REQ_RECLAIM        2
>> +
>> +#define RMI_DONATE_SIZE_MASK        3UL
>> +#define RMI_DONATE_COUNT_MASK        GENMASK(15, 2)
>> +#define RMI_DONATE_CONTIG_MASK        BIT(16)
>> +#define RMI_DONATE_STATE_MASK        GENMASK(18, 17)
>> +
>> +#define RMI_DONATE_SIZE(req)        FIELD_GET(RMI_DONATE_SIZE_MASK, req)
>> +#define RMI_DONATE_COUNT(req)        FIELD_GET(RMI_DONATE_COUNT_MASK, 
>> req)
>> +#define RMI_DONATE_CONTIG(req)        
>> FIELD_GET(RMI_DONATE_CONTIG_MASK, req)
>> +#define RMI_DONATE_STATE(req)        FIELD_GET(RMI_DONATE_STATE_MASK, 
>> req)
>> +
> 
> As above, RMI_DONATE_{SIZE, COUNT, CONTIG, STATE}_MASK are used for once 
> in this
> header file. So their definitions can be dropped by modifying the 
> followup macros,
> as below. Some enhancements are also applicable: (a) Use 'BLOCK' to 
> indicate the
> unit encoded in the request. (b) The macros are put into order from MSB 
> to LSB.
> 
> #define RMI_DONATE_STATE(req)        FIELD_GET(GENMASK(18, 17), req)
> #define RMI_DONATE_CONTIG(req)        FIELD_GET(GENMASK(16, 16), req)
> #define RMI_DONATE_BLOCK_COUNT(req)    FIELD_GET(GENMASK(15, 2), req)
> #define RMI_DONATE_BLOCK_SIZE(req)    FIELD_GET(GENMASK(1, 0), req)

Same as above.

> 
>> +#define RMI_OP_MEM_DELEGATED        0
>> +#define RMI_OP_MEM_UNDELEGATED        1
>> +#define RMI_OP_MEM_CONDITIONAL        2
>> +
> 
> B4.6.40 RmiOpMemContig type is missed here and they should be used in 
> the c code.
> 
> #define RMI_OP_MEM_NON_CONTIG    0
> #define RMI_OP_MEM_CONTIG    1
> 
> In the c code, we shall have:
> 
> if (RMI_DONATE_CONTIG(req) == RMI_OP_MEM_CONTIG)) {
>     ...
> } else {
>     ...
> }
> 

Does it make much sense though ? I prefer

if (RMI_DONATE_CONTIG(req))

to


if (RMI_DONATE_CONTIG(req) == RMI_OP_MEM_CONTIG)) {


than having a field for a single bit values. I am happy to change
this if there is strong preference to the other.


> Similarly, B4.6.39 RmiOpCanCancel type is missed here and they should be 
> used in
> the c code.
> 
> #define RMI_OP_CANNOT_CANCEL    0
> #define RMI_OP_CAN_CANCEL    1
> 
> In the c code, we shall have:
> 
> if (RMI_RETURN_CAN_CANCEL(ret) == RMI_OP_CAN_CANCEL) {
>      ...
> } else {
>      ...
> }
> 

Same as above.

>> +#define RMI_ADDR_TYPE_NONE        0
>> +#define RMI_ADDR_TYPE_SINGLE        1
>> +#define RMI_ADDR_TYPE_LIST        2
>> +
>> +#define RMI_ADDR_RANGE_SIZE_MASK    GENMASK(1, 0)
>> +#define RMI_ADDR_RANGE_COUNT_MASK    GENMASK(PAGE_SHIFT - 1, 2)
>> +#define RMI_ADDR_RANGE_ADDR_MASK    (PAGE_MASK & GENMASK(51, 0))
>> +#define RMI_ADDR_RANGE_STATE_MASK    GENMASK(63, 62)
>> +
>> +#define RMI_ADDR_RANGE_SIZE(ar)        
>> (FIELD_GET(RMI_ADDR_RANGE_SIZE_MASK, \
>> +                           (ar)))
>> +#define RMI_ADDR_RANGE_COUNT(ar)    
>> (FIELD_GET(RMI_ADDR_RANGE_COUNT_MASK, \
>> +                           (ar)))
>> +#define RMI_ADDR_RANGE_ADDR(ar)        ((ar) & RMI_ADDR_RANGE_ADDR_MASK)
>> +#define RMI_ADDR_RANGE_STATE(ar)    
>> (FIELD_GET(RMI_ADDR_RANGE_STATE_MASK, \
>> +                           (ar)))
>> +
> 
> I guess it wouldn't a bad idea to explictly indicate 'BLOCK' in the 
> definitions, as
> below. Some improvements are applicated either: (a) 'ar' is renamed to 
> 'r'; (b) The
> excessive parentheses are dropped to follow the patterns we already had; 
> (c) For
> RMI_ADDR_RANGE_ADDR(r), FIELD_GET() is used.
> 
> #define RMI_ADDR_RANGE_BLOCK_SIZE_MASK        GENMASK(1, 0)
> #define RMI_ADDR_RANGE_BLOCK_COUNT_MASK        GENMASK(PAGE_SHIFT - 1, 2)
> #define RMI_ADDR_RANGE_ADDR_MASK        (PAGE_MASK & GENMASK(51, 0))
> #define RMI_ADDR_RANGE_STATE_MASK        GENMASK(63, 62)
> 
> #define RMI_ADDR_RANGE_BLOCK_SIZE(r)        
> FIELD_GET(RMI_ADDR_RANGE_SIZE_MASK, r)
> #define RMI_ADDR_RANGE_BLOCK_COUNT(r)        
> FIELD_GET(RMI_ADDR_RANGE_COUNT_MASK, r)
> #define RMI_ADDR_RANGE_ADDR(r)                
> FIELD_GET(RMI_ADDR_RANGE_ADDR_MASK, r)
> #define RMI_ADDR_RANGE_STATE(r)                
> FIELD_GET(RMI_ADDR_RANGE_STATE_MASK, r)

Ack

> 
>> +enum rmi_ripas {
>> +    RMI_EMPTY = 0,
>> +    RMI_RAM = 1,
>> +    RMI_DESTROYED = 2,
>> +    RMI_DEV = 3,
>> +};

>> +#define RMI_FEATURE_REGISTER_1_RMI_GRAN_SZ_4KB    BIT(0)
>> +#define RMI_FEATURE_REGISTER_1_RMI_GRAN_SZ_16KB    BIT(1)
>> +#define RMI_FEATURE_REGISTER_1_RMI_GRAN_SZ_64KB    BIT(2)
>> +#define RMI_FEATURE_REGISTER_1_HASH_SHA_256    BIT(3)
>> +#define RMI_FEATURE_REGISTER_1_HASH_SHA_384    BIT(4)
>> +#define RMI_FEATURE_REGISTER_1_HASH_SHA_512    BIT(5)
>> +#define RMI_FEATURE_REGISTER_1_MAX_RECS_ORDER    GENMASK(9, 6)
>> +#define RMI_FEATURE_REGISTER_1_L0GPTSZ        GENMASK(13, 10)
>> +#define RMI_FEATURE_REGISTER_1_PPS        GENMASK(16, 14)
>> +
>> +#define RMI_FEATURE_REGISTER_2_DA        BIT(0)
>> +#define RMI_FEATURE_REGISTER_2_DA_COH        BIT(1)
>> +#define RMI_FEATURE_REGISTER_2_VSMMU        BIT(2)
>> +#define RMI_FEATURE_REGISTER_2_ATS        BIT(3)
>> +#define RMI_FEATURE_REGISTER_2_PDEV_MAX_VDEVS_ORDER    GENMASK(7, 4)
>> +#define RMI_FEATURE_REGISTER_2_VDEV_KROU    BIT(8)
>> +#define RMI_FEATURE_REGISTER_2_NON_TEE_STREAM    BIT(9)
>> +#define RMI_FEATURE_REGISTER_2_REALM_MAX_VDEVS_ORDER    GENMASK(14, 10)
>> +
>> +#define RMI_FEATURE_REGISTER_3_MAX_NUM_AUX_PLANES    GENMASK(3, 0)
>> +#define RMI_FEATURE_REGISTER_3_RTT_PLANE        GENMASK(5, 4)
>> +#define RMI_FEATURE_REGISTER_3_RTT_S2AP_INDIRECT    BIT(6)
>> +
>> +#define RMI_FEATURE_REGISTER_4_MEC_COUNT        GENMASK(63, 0)
>> +
> 
> We would reorder those feature register definitions from MSB ro LSB :-)

Ack

Thanks for your review.

Cheers
Suzuki